This invention relates to an electro-mechanical system for automatically delivering a precise volume of hot water from a heated water tank to a beverage brewer such as a coffee-brewer, upon command, and also permitting variable portions of hot water to be manually drawn from the tank by means of a faucet.
Generally speaking, systems of this type have been known in the prior art. See for example U.S. Pat. No. 4,464,981 issued to K. W. Stover on Aug. 14, 1984 which discloses a system for automatically delivering a batch of hot water from a hot water tank to a brewing funnel and also permits variable quantities of hot water, usually in cup sizes, to be manually withdrawn from the tank. The Stover system delivers a batch of hot water to a brewing funnel by using a timer to control the operation of a solenoid valve which delivers unheated water from a suitable remote source to a lower end of a heated tank such that the cooler unheated water flowing into the bottom of the tank displaces less dense heated water already in the tank upwardly for draw off to a brewing funnel. In addition, the Stover system employs a faucet on the heated tank which permits varying amounts of hot water to be manually drawn and the minimum level of water permitted in the tank is sensed and controlled by a resistance probe sensor and control circuit.
A problem that arises in the Stover system is due to the fact that a timer is used to control the solenoid valve which supplies source water to the tank, which timer thus controls the amount or volume of hot water displaced upwardly in the tank for delivery to the brewing funnel. Where the source water pressure varies, the amount of source water delivered by the solenoid valve to the tank in a given amount of time can vary. This, in turn, causes the amount of upwardly displaced hot water to be drawn to the brewing funnel to vary from one batch to another, which alters the strength of the beverage being brewed from one batch to another. It is therefore not accurate to state that the Stover system always delivers a precise volume of hot water to a brewer.
By means of invention, so long as the source water pressure is at least sufficient to operate and open a conventional dump valve, this difficulty as well as others encountered in the prior art is essentially overcome.